Spaceflight Insider

UPDATE: Curiosity to resume use of robotic arm in a few days

Curiosity's arm as seen on Spaceflight Insider

This photo from the Navigation Camera (Navcam) on NASA's Curiosity Mars rover shows the position in which the rover held its arm for several days after a transient short circuit triggered onboard fault-protection programming to halt arm activities on Feb. 27, 2015. Photo Credit: NASA/JPL-Caltech/MSSS

Managers of NASA’s Curiosity rover mission plan to resume the use of its robotic arm later this week while continuing to analyze what appears to be an intermittent short in the rover’s drill. On Feb. 27, Curiosity’s fault protection systems halted the transfer of sample rock powder from one device on the rover’s robotic arm to another. The mission team has avoided driving the rover or moving its robotic arm for several days while engineers conducted diagnostic tests to determine the cause of the incident. Science observations using instruments on the rover’s mast have continued, as well as environmental monitoring by its weather station.

“Diagnostic testing this week has been productive in narrowing the possible sources of the transient short circuit,” said Curiosity Project Manager Jim Erickson of NASA’s Jet Propulsion Laboratory, Pasadena, California. “The most likely cause is an intermittent short in the percussion mechanism of the drill. After further analysis to confirm that diagnosis, we will be analyzing how to adjust for that in future drilling.”

Curiosity’s drill uses both rotation and hammering, or percussion, to drill into Martian rocks and collect samples of pulverized rock powder for delivery to scientific instruments inside the rover.

MAHLI image of a Curiosity drill site as seen on Spaceflight Insider

Curiosity’s Mars Hand Lens Imager captured this image of a hole drilled by Curiosity. The rover’s percussion system is what shakes the sample off of the drill. Image Credit: NASA/JPL-Caltech

The short on Feb. 27 occurred while Curiosity was in the early stages of transferring rock powder from the grooves of its drill into a mechanism that sieves and portions the powder. During this operation, the rover used the percussion action of its drill to shake the powder loose.

On Thursday, March 5, engineers received the results from a test on the rover that used the percussion action of Curiosity’s drill in a similar manner. During the third of 180 repeats of the up-and-down action, an apparent short occurred for less than one-hundredth of a second.  This small and fleeting short would have been enough to trigger the rover’s fault protection systems under the parameters that were in place on Feb. 27.

The rover team will conduct further tests to characterize the short before moving the rover’s arm from its current position, in case the short does not appear when the orientation of the arm is different.

Following the tests, the rover team expects to finish processing the sample powder currently held in the arm and then deliver portions of the sample to the rover’s scientific instruments.

Once the sample material is processed, the team plans to drive Curiosity away from its current location of Pahrump Hills, exiting through a narrow valley called “Artist’s Drive”, which will lead the rover along a strategically planned route higher on the basal layer of Mount Sharp.


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Jim Sharkey is a lab assistant, writer and general science enthusiast who grew up in Enid, Oklahoma, the hometown of Skylab and Shuttle astronaut Owen K. Garriott. As a young Star Trek fan he participated in the letter-writing campaign which resulted in the space shuttle prototype being named Enterprise. While his academic studies have ranged from psychology and archaeology to biology, he has never lost his passion for space exploration. Jim began blogging about science, science fiction and futurism in 2004. Jim resides in the San Francisco Bay area and has attended NASA Socials for the Mars Science Laboratory Curiosity rover landing and the NASA LADEE lunar orbiter launch.

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